Laminate-controlling light autonomously and window using the same

ABSTRACT

There are provided laminated bodies or laminated body-containing windows, which comprise isotropic aqueous solutions obtained by dissolving a water-soluble polysaccharide derivative having nonionic amphipathic functional groups in an aqueous medium composed of water and an amphipathic substance, laminated between plates that are at least partially transparent and allow direct vision of the isotropic aqueous solutions, wherein there are added to the isotropic aqueous solutions in appropriate amounts ultraviolet absorbers comprising nonionic or ionic benzophenone derivatives or benzotriazole derivatives which are highly weather resistant and uniformly dissolve in the isotropic aqueous solutions. The isotropic aqueous solutions are transparent and become opaque upon irradiation with light, and exhibit stable reversible change, in order to provide vastly improved weather resistance to the laminated bodies against exposure to sunlight rays over prolonged periods of time.

TECHNICAL FIELD

The present invention relates to laminated bodies enclosing isotropicaqueous solutions which undergo reversible change between transparencyand opacity in response to temperature changes caused by heating withsolar energy or the like, as well as to windows which employ them.

BACKGROUND ART

In recent years, light regulating glass capable of controllingpenetration of sunlight rays has become a topic of interest for energyconservation, comfort, etc. The present specification will refer mainlyto window glass to be used for windows in buildings, automobiles and thelike, but the laminated bodies of the invention are widely applicable,with no limitation to windows.

The present inventors focused on the fact that windows are directlyexposed to sunlight rays. By effectively utilizing the temperaturedifference between the presence and absence of solar radiation andbetween seasons, it became possible to develop revolutionaryself-responding light regulating laminated bodies which, when exposed tosunlight rays in the high temperature summer season, naturally becomeopaque and block the sunlight rays. More specifically, for example, U.S.Pat. No. 5,615,040 (corresponding to Japanese Unexamined PatentPublication HEI No. 6-255016) is cited in Journal of Japan Solar EnergySociety, Taiyo Energy, Vol. 27, No. 5 (2001), pp. 14-20. The basicstructure of the invention described therein is a laminated body inwhich an isotropic aqueous solution is sealed between a pair of plates.The isotropic aqueous solution comprises at least a water-solublepolysaccharide derivative, an amphipathic substance and water. Theprinciple depends on a stably reversible temperature-dependent sol-gelphase transition. At low temperature, the molecules are uniformlydissolved to produce an isotropic aqueous solution (sol state), while athigh temperature a phase transition occurs as the dissolved moleculesaggregate into a flocculated state (gel state). In the gel state, thedifference in density between the solvent and the fine aggregatescreates opacity due to light scattering, thereby blocking about 80% oflight. When the laminated body is used to construct a window, thetransparent state is maintained to permit penetration of sunshine whenthe temperature of the laminated body remains lower in the winterseason, while heating by direct sunlight rays during the summer seasonproduces opacity which cuts approximately 80% of the sun's rays, therebyproviding an energy-conserving, light-regulating window glass. Thelaminated body satisfies the following fundamental conditions alsolisted in the aforementioned document.

1) Phase changes between the transparent and opaque state must bereversible.

2) Reversible changes must be able to be repeated without phaseseparation.

3) The material must be weather resistant.

This laminated body has already been tested as window glass by thepresent inventors, but it was found that the weather resistance neededto be further improved for it to be suitable for common use as windowglass which is exposed to constant sunlight. The results of actualrooftop exposure testing in a Tokyo district using a laminated bodyassembled with a satisfactory sealed structure indicated an increase inthe initial opacity temperature already within about 3 years, even with5 mm-thick float glass. The present inventors diligently examinedmethods of adding ultraviolet absorbers to the isotropic aqueoussolution and as a result succeeded in developing a laminated bodyexhibiting revolutionary high weather resistance having features 1) and2) above, and adequately satisfying condition 3) above.

Window glass must exhibit high weather resistance for use over longperiods of 10 years or more and even 20 or 30 years. It should also beas light and thin as possible for reduced load on building frames andcompatibility with window frames, as well as for more advantageousmanufacturing, transport, construction and the like. The presentinventors had also previously examined methods of imparting glass panelswith ultraviolet-blocking functions, but because of problems of such ascoloring and weight increase and the need for special working, suchmethods were not generally suitable. The present inventors thereforeconducted more detailed examination focusing on various ultravioletabsorbers in order to vastly improve the weather resistance of theisotropic aqueous solution itself.

Previously, there have existed only written references to the generalconcept of adding ultraviolet absorbers that dissolve in isotropicaqueous solutions for improved weather resistance (benzophenonederivatives, benzotriazole derivatives, salicylic acid esterderivatives, etc.), as also referred to by the present inventors in theaforementioned document, and the patent document mentions onlySumisorb•110S (2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) bySumitomo Chemical Co., Ltd. as a water-soluble ultraviolet absorber. Wetherefore tested two types of laminated bodies, comprising an isotropicaqueous solution containing no ultraviolet absorber or an isotropicaqueous solution containing Sumisorb•110S by Sumitomo Chemical Co.,Ltd., by an ultraviolet exposure test as described in the examples, andfound that air bubbles were generated in both cases from about 50 hoursto 100 hours, producing unrecoverable irregularities.

DISCLOSURE OF THE INVENTION

The present invention has been accomplished with the purpose ofovercoming the problems of the prior art described above, and its gistis a laminated body or a laminated body-containing window, whichcomprises an isotropic aqueous solution obtained by dissolving awater-soluble polysaccharide derivative having a nonionic amphipathicfunctional group in an aqueous medium composed of water and anamphipathic substance, the solution being laminated between plates thatare at least partially transparent and allow direct vision of theisotropic aqueous solution, wherein there is added to the isotropicaqueous solution in an appropriate amount an ultraviolet absorbercomprising a nonionic or ionic benzophenone derivative or benzotriazolederivative which is highly weather resistant and uniformly dissolves inthe isotropic aqueous solution. It was found that this produces atransparent isotropic aqueous solution which becomes opaque whenirradiated with light and exhibits stable reversible change, in order toprovide vastly improved weather resistance to laminated bodies whenexposed to sunlight rays over prolonged periods of time.

In other words, the invention provides a laminated body which comprisesan isotropic aqueous solution obtained by dissolving 100 parts by weightof a water-soluble polysaccharide derivative having a weight-averagemolecular weight of about 10,000 to about 200,000 and having a nonionicamphipathic functional group, in about 100 to about 2000 parts by weightof an aqueous medium composed of water in an amount of about 25 to about450 with respect to 100 parts by weight of the polysaccharide derivativeand an amphipathic substance with a molecular weight of about 60 toabout 5000, laminated between plates that are partially transparent andallow direct vision of the aqueous solution, wherein there is added inan amount of 0.01-10 parts by weight with respect to 100 parts by weightof the isotropic aqueous solution at least one compound selected fromthe group consisting of nonionic benzophenone derivatives andbenzotriazole derivatives having solubility of 1 g or greater in theamphipathic substance at 20° C. and ionic benzophenone derivatives andbenzotriazole derivatives with an ionic functional group bonded to thebenzene ring via a chain portion and having solubility of 1 g or greaterin water at 20° C.

The invention further provides a window containing a laminated bodywhich comprises an isotropic aqueous solution obtained by dissolving 100parts by weight of a water-soluble polysaccharide derivative having aweight-average molecular weight of about 10,000 to about 200,000 andhaving a nonionic amphipathic functional group, in about 100 to about2000 parts by weight of an aqueous medium composed of water in an amountof about 25 to about 450 with respect to 100 parts by weight of thepolysaccharide derivative and an amphipathic substance with a molecularweight of about 60 to about 5000, the solution being laminated betweenplates that are partially transparent and allow direct vision of theaqueous solution, wherein there is added in an amount of 0.01-10 partsby weight with respect to 100 parts by weight of the isotropic aqueoussolution at least one compound selected from the group consisting ofnonionic benzophenone derivatives and benzotriazole derivatives havingsolubility of 1 g or greater in the amphipathic substance at 20° C. andionic benzophenone derivatives and benzotriazole derivatives with anionic functional group bonded to the benzene ring via a chain portionand having solubility of 1 g or greater in water at 20° C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an embodiment of a laminated bodyaccording to the invention.

FIG. 2 is a cross-sectional view of an embodiment of a laminated body ofthe invention having a gas layer additionally situated therein.

FIG. 3 is a cross-sectional view of an embodiment of a laminated body ofthe invention having isotropic aqueous solution layers with differentcompositions.

FIG. 4 is a graph showing the change in transmittance of a laminatedbody of the invention between the transparent state and the opaquestate.

BEST MODE FOR CARRYING OUT THE INVENTION

As described in the aforementioned patent document, the aqueous solutionused for the present invention is an isotropic aqueous solution with abasic composition comprising a water-soluble polysaccharide derivativehaving an added nonionic amphipathic functional group (hereinafterreferred to as “amphipathic polysaccharide derivative”), and anamphipathic substance and water, wherein the solution undergoes a stablereversible change between transparency and opacity based on temperaturechanges.

The present inventors focused on the fact that amphipathic substances inisotropic aqueous solutions in the presence of water also have solventaction. We selected benzophenone derivatives and benzotriazolederivatives having satisfactory ultraviolet absorption properties andhigh light stability, and examined in detail the affinity relationshipbetween water, amphipathic substances and amphipathic polysaccharidederivatives. As a result, it was found that benzophenone derivatives andbenzotriazole derivatives exist which dissolve uniformly in isotropicaqueous solutions, and a vast improvement in weather resistance ofisotropic aqueous solutions was successfully achieved using them. Onegroup of such derivatives are nonionic benzophenone derivatives andbenzotriazole derivatives having 20° C. solubility of 1 g or greater andpreferably 3 g or greater in amphipathic substances which are liquid atroom temperature. Preferred are nonionic benzophenone derivatives andbenzotriazole derivatives having 20° C. solubility of 1 g or greater andpreferably 3 g or greater in polyoxypropylene trimethylolpropane havinga molecular weight of about 400 (hereinafter, TP400).

Another group of such derivatives are ionic benzophenone derivatives andbenzotriazole derivatives with an ionic functional group bonded to thebenzene ring not directly but rather via a chain portion, and having 20°C. solubility of 1 g or greater and preferably 3 g or group in water,for guaranteed light stability of the ultraviolet absorber itself. Here,a “chain portion” refers to a functional group inserted between thebenzene ring and the ionic functional group (for example, methylene,ethylene, ethylene oxide, propylene oxide, ether, ester, etc.). Anonionic benzophenone derivative or benzotriazole derivative may also beused in admixture with an ionic benzophenone derivative or benzotriazolederivative.

Nonionic benzophenone derivatives and benzotriazole derivatives usefulfor the present invention will now be described. Nonionic benzophenonederivatives and benzotriazole derivatives generally lack affinity withwater due to the strong hydrophobicity of the benzene ring, but it wasfound that benzophenone derivatives and benzotriazole derivatives whichdissolve at 1 g or greater in TP400 can stably dissolve in isotropicaqueous solutions due to the solvent effect of TP400 and due tointeraction between the amphipathic functional groups of amphipathicpolysaccharide derivatives. It was consequently discovered thatamphipathic polysaccharide derivatives dissolved in isotropic aqueoussolutions are protected from ultraviolet rays and vastly increase theweather resistance of the isotropic aqueous solutions. As one method ofpreparing an isotropic aqueous solution, a benzophenone derivative orbenzotriazole derivative is heated to dissolution in TP400 and thenwater and, if necessary, additives are added and mixed therewith, andfinally an amphipathic polysaccharide derivative is added thereto priorto thorough mixing to obtain a uniform isotropic aqueous solution.

Representative examples of ultraviolet absorbers include2,2′,4,4′-tetrahydroxybenzophenone (hereinafter, UV-106) and2-(2,4-dihydroxyphenyl)-2H-benzotriazole (hereinafter, UV-7011), whichgive completely transparent isotropic aqueous solutions. As a typicalamphipathic polysaccharide derivative there may be mentionedhydroxypropyl cellulose (hydroxypropyl groups: 62.4%, 2% aqueoussolution viscosity: 8.5 cps/20° C., weight-average molecular weight:˜60,000; hereinafter, HPC) and as a typical amphipathic substance theremay be mentioned TP400.

According to experiments conducted by the present inventors, adding 6parts by weight of UV-106 to 100 parts by weight of TP400, heating themixture to dissolution and returning it to room temperature (20° C.)yielded a completely transparent solution. By adding 87 parts by weightof water to 25 parts by weight of this solution and stirring at roomtemperature, an opaque state was produced due to separation of theUV-106 (TP400 and water are uniformly miscible at room temperature).Surprisingly, however, when 50 parts by weight of HPC was further addedand the mixture was adequately stirred, the opacity totally cleared togive a completely transparent isotropic aqueous solution. The isotropicaqueous solution containing UV-106, when heated, was sufficiently opaqueto uniformly block light, and was stably reversible and exhibited highweather resistance. Next, there was prepared a mixture ofHPC/TP400/UV-7011/water in a composition of 50/50/1.3/87 parts byweight. Mixing of TP400 and UV-7011, as with UV-106, produced acompletely transparent solution which became opaque with addition ofwater and finally upon addition of HPC produced a completely transparentisotropic aqueous solution. This isotropic aqueous solution as well,when heated, was sufficiently opaque to uniformly block light, and wasstably reversible and exhibited high weather resistance.

Considering that the major use of the laminated body of the inventionwill be in windows, it is preferred to obtain a water-like completelycolorless transparent state. A careful examination was thereforeconducted in regard to benzophenone derivatives and benzotriazolederivatives which give completely transparent isotropic aqueoussolutions. The amount thereof added may be about 0.01 wt % to 10 wt %,and preferably about 0.1 wt % to 5 wt %, in the isotropic aqueoussolution. At lower amounts the effect may be insufficient, and atgreater amounts no further improvement in weather resistance isproduced.

It was discovered that in order for nonionic benzophenone derivatives tomix with isotropic aqueous solutions in a water-like completelytransparent state, it is extremely important for them to havehydrophilic functional groups such as hydroxyl groups, represented asR₃-R₁₀, in addition to the hydroxyl groups represented by R₁ or R₂ whichcontribute to intramolecular hydrogen bonding, as shown in generalformula 1 below, so that the benzophenone derivatives exhibit higheraffinity for water, amphipathic substances and amphipathicpolysaccharide derivatives and the interaction between all of thedissolved substances is in a satisfactory hydrophilic-hydrophobicbalance, to thereby obtain a stably reversible and water-liketransparent isotropic aqueous solution. This may be accomplished, forexample, by adding functional groups such as hydroxyl, polyglycerin,polyethylene oxide or sugar residues.

Specifically, R₁ and R₂ in general formula 1 each represent hydrogen orhydroxyl, with at least one of R₁ and R₂ being hydroxyl, and R₃-R₁₀ eachrepresent hydrogen, C₁₋₄ alkyl (for example, methyl, ethyl, etc.), C₁₋₄alkoxy (for example, methoxy, ethoxy, etc.), hydroxyl, polyglycerin,polyethylene oxide (for example, Japanese Unexamined Patent PublicationHEI No. 7-109447) or 0-(R₁₁)_(n)-A (where A represents an unprotectedsugar residue (a residue lacking one hydroxyl group from, for example, amonosaccharide such as glucose or galactose, a disaccharide such astrehalose or maltose or a trisaccharide such as maltotriose), and R₁₁represents a direct bond (n=0), C₁₋₄ alkylene or C₁₋₄ alkyleneoxide(where n is an integer of 1 to 6)) (for example, Japanese UnexaminedPatent Publication HEI No. 6-87879, Japanese Unexamined PatentPublication HEI No. 6-135985), with at least one from among R₃ to R₁₀being hydroxyl, polyglycerin, polyethylene oxide or O—(R₁₁)_(n)-A.

Preferably, no more than one of the hydroxyl groups of R₃ to R₁₀ ispresent on each benzene ring in order to prevent yellowing, andspecifically such compounds include, for example,2,4-dihydroxybenzophenone, 2,4,4′-trihydroxybenzophenone,2,2′,4-trihydroxybenzophenone, UV-106 and2,4-dihydroxy-4′-methoxybenzophenone. Polyethylene oxide groups increasethe number of ethylene oxide units while resulting in greater affinity,and they may be present in a number of 2-100 and preferably about 5-30;specifically such compounds include, for example,2-hydroxy-4-polyethyleneoxide benzophenone and2-hydroxy-4-polyethyleneoxide-4′-methoxybenzophenone. Compounds ofgeneral formula 1 above include, for example, compounds represented bygeneral formula 2 below.

(wherein R₁ and R₄ each represent hydrogen, hydroxyl or C₁₋₄ alkoxy, Arepresents a glucose residue, trehalose residue or maltose residue, R₁₁represents C₁₋₄ alkylene or C₁₋₄ alkyleneoxide, n is 1 or 2, and fromthe standpoint of water-solubility and industrial properties, preferablythe alkoxy group is methoxy or ethoxy, the alkylene group is methyleneor ethylene and the alkyleneoxide group is ethyneoxide or propyneoxide).

It was also discovered that in order for nonionic benzotriazolederivatives to mix with isotropic aqueous solutions in a water-liketransparent state, it is extremely important for them to havehydrophilic functional groups such as hydroxyl groups, represented asR₃-R₆, in addition to the hydroxyl group represented by R₁ whichcontributes to intramolecular hydrogen bonding, as shown in generalformula 3 below, so that the benzotriazole derivatives exhibit higheraffinity for water, amphipathic substances and amphipathicpolysaccharide derivatives and the interaction between all of thedissolved substances is in a satisfactory hydrophilic-hydrophobicbalance, to thereby obtain a stably reversible and water-liketransparent isotropic aqueous solution. This may be accomplished, forexample, by adding functional groups such as hydroxyl, polyglycerin,polyethylene oxide or sugar residues.

Specifically, R₁ in general formula 3 represents hydroxyl, and R₃-R₆each represent hydrogen, C₁₋₄ alkyl, c₁₄ alkoxy, hydroxyl, polyglycerin,polyethylene oxide or O—(R₁₁)_(n)-A (where A represents an unprotectedsugar residue (a residue lacking one hydroxyl group from, for example, amonosaccharide such as glucose or galactose, a disaccharide such astrehalose or maltose or a trisaccharide such as maltotriose), and R₁₁represents a direct bond (n=0), C₁₋₄ alkylene or C₁₋₄ alkyleneoxide(where n is an integer of 1 to 6)), with at least one from among R₃ toR₆ being hydroxyl, polyglycerin, polyethylene oxide or O—(R₁₁)_(n)-A.

Preferably only one of the hydroxyl groups of R₃ to R₆ is present inorder to prevent yellowing, and specifically such compounds include, forexample, 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and the like.Polyethylene oxide groups increase the number of ethylene oxide unitswhile resulting in greater affinity, and they may be present in a numberof 2-100 and preferably about 3-30; specifically such compounds include,for example, 2-(2,4-dihydroxyphenyl)-2H-benzotriazole havingpolyethylene oxide added to the 4-position hydroxyl group. The groupO—(R₁₁)_(n)-A may be the same as mentioned above for benzophenonederivatives. In addition, halogens such as chlorine or C₁₋₄ alkyl groupsmay be added to the benzene ring of the benzotriazole, although nospecial effect according to the invention is obtained.

Ionic benzophenone derivatives and benzotriazole derivatives will now bedescribed. According to experiments conducted by the present inventors,benzophenone derivatives and benzotriazole derivatives having ionicfunctional groups directly bonded to the benzene ring producedwater-like transparent isotropic aqueous solutions, but such ultravioletabsorbers exhibited inferior light stability, and photodegradation ofthe ultraviolet absorbers caused the isotropic aqueous solutions togenerate air bubbles and undergo severe yellowing, rendering themunsuitable for use. As a result of further diligent examination it wasfound that ionic benzophenone derivatives and benzotriazole derivativeswhich have the ionic functional groups bonded to the benzene via chainportions and which dissolve in water yield water-like transparentisotropic aqueous solutions which are stably reversible and exhibit highweather resistance. Such ionic functional groups include, for example,sulfonic acid groups, carboxylic acid groups, phosphoric acid groups andammonium groups. The solubility in water at 20° C. may be 1 g or greaterand preferably 3 g or greater.

Specifically, these are compounds wherein R₁ and R₂ in general formula 1each represent hydrogen or hydroxyl, with at least one of R₁ and R₂being hydroxyl, and R₃-R₁₀ each represent hydrogen, C₁₋₄ alkyl (forexample, methyl, ethyl, etc.), C₁₋₄ alkoxy (for example, methoxy,ethoxy, etc.), or an ionic functional group with a chain portion, withat least one from among R₃ to R₁₀ being an ionic functional hydroxylgroup with a chain portion. Such ionic functional groups undergo ionicdissociation after their addition to isotropic aqueous solutions, andthe pH of the isotropic aqueous solutions may be 5-9 and preferably 6-8.The chain portion may be introduced via the hydroxyl groups of R₃ to R₁₀and for example, ethylene oxide groups are useful.

Specifically, ionic ultraviolet absorbers may be obtained, for example,by reactions for modification of the 4-position hydroxyl group, as apublicly known method widely used for synthesis of ultravioletabsorbers, surfactants and the like, and the following Compound Nos. 1-6may be mentioned as examples, where “n” is not particularly restrictedbut is preferably about 1 to 6.

Compound No. 1 (benzotriazole derivative, soluble in water at 20° C.:3.6 g) will be explained as a concrete example. Compound No. 1 was addedat 1.3 parts by weight to 87 parts by weight of water, heated todissolution and returned to room temperature (20° C.) to obtain atransparent aqueous solution. To this aqueous solution there were addedin order 25 parts by weight of TP400 and 50 parts by weight of HPC, andthe mixture was subsequently stirred to obtain a water-like transparentuniform isotropic aqueous solution. The isotropic aqueous solution, whenheated, had sufficient opacity to uniformly block light, and the statewas stably reversible with high weather resistance exhibited.

The amphipathic polysaccharide derivatives and amphipathic substancesuseful for the present invention will now be explained, as is alsoexplained in detail in the aforementioned patent document. Asamphipathic polysaccharide derivatives there may be mentionedpolysaccharides (for example, cellulose, pullulan, dextran, etc.) havingadded nonionic functional groups (for example, hydroxypropyl, etc.),which dissolve uniformly to high concentrations of about 25 to about 50wt % in water at room temperature to form aqueous solutions, and producean opaque state as the temperature increases due to the hydrophobicbonding effect. Among these, cellulose derivatives are important fortheir high stability. The following description will focus mainly oncellulose derivatives, unless otherwise specified, with theunderstanding that the invention is not limited thereto. A smallerweight-average molecular weight of the amphipathic polysaccharidederivative results in less aggregation and weaker opacity, while alarger weight-average molecular weight causes too much aggregation andphase separation, due to the polymer effect, and therefore neithersituation is suitable. Consequently, the weight-average molecular weightof the amphipathic polysaccharide derivative may be in the range ofabout 10,000 to about 200,000 and preferably in the range of about15,000 to about 100,000. In the following description, hydroxypropyl hasbeen selected as an example of the functional group added to thecellulose and therefore the focus will be on hydroxypropyl cellulose,but with the understanding that the invention is not limited thereto.

The concentration of the amphipathic polysaccharide derivative of theinvention does not need to be particularly high, because if it is toohigh the hydrophobic bonding effect may be insufficient and even ifphase separation does not occur, the opaque light-blocking effect may beweaker, the viscosity may be too high and it may be difficult toaccomplish lamination without air bubbles; the concentration of theamphipathic polysaccharide derivative is therefore preferably no greaterthan about 50% with respect to the water. However, it was discoveredthat if an aqueous medium (a water/amphipathic substance mixture) isselected as a solvent, even with a composition of, for example, 75 wt %HPC (with the remaining 25 wt % a 5 wt % aqueous sodium chloridesolution), and an amphipathic substance such as TP400, for example, isadded as a solvent to a proportion of HPC of approximately 30 wt % withrespect to the total, an opaque change occurs at about 67° C. If thesolvent action of the amphipathic substance is utilized in this manner,the concentration (the proportion of the amphipathic polysaccharidederivative with respect to the water) is not limited to below about 50wt %. From the standpoint of practical utility, production isfacilitated by minimizing the overall proportion of the amphipathicpolysaccharide derivative to achieve a lower viscosity. Thus, from theviewpoint of opaque aggregation and reversible stability, the amount ofwater (which may also include a temperature shifting agent) may be fromabout 25 to about 450 parts by weight and preferably from about 50 toabout 300 parts by weight to 100 parts by weight of the amphipathicpolysaccharide derivative.

The amphipathic substance acts to prevent phase separation when theisotropic aqueous solution of the amphipathic polysaccharide derivativeundergoes opaque aggregation. Even with addition of the amphipathicsubstance, however, separation of the water will tend to occur if theconcentration of the amphipathic polysaccharide derivative with respectto the water is about 18 wt % or below and more definitely about 25 wt %or below.

The amphipathic substance is a compound having both a hydrophilic groupand a hydrophobic group, and either dissolving or uniformly dispersingin water at room temperature. Hydrophilic groups include, for example,hydroxyl, ethylene oxide, ether bonds, ester bonds, amide bonds and thelike. Hydrophobic groups include, for example, lower aliphatic groupssuch as C₁₋₄ alkyl groups, and when the hydrophilic group is large, suchas polyethylene oxide or an ionic group (for example, sulfonic acid,carboxyl, phosphoric acid, an amphoteric group, etc.), the functionalgroup may include a large hydrophobic group such as a C₅₋₂₅ largealiphatic group, or an aromatic benzene group, benzyl group, phenolgroup or the like. If the molecular weight of the amphipathic substanceis too large, the polymer effect will tend to result in irreversiblechange and lack of uniformity, while large molecular weights do notnecessarily exhibit excellent effects and instead may increase theviscosity of the isotropic aqueous solution and impair its workability.The molecular weight is therefore limited to no greater than theoligomer range of about 5000, and is preferably no greater than about3000. If the molecular weight is too small the effect will tend to bereduced, and it is therefore at least about 60.

Specific examples of amphipathic substances include2-ethyl-2-(hydroxymethyl)-1,3-propanediol, 2,3,4-pentanetriol,diethyleneglycol monobutyl ether, diethyleneglycol monobenzyl ether,dipropyleneglycol monomethyl ether, tripropyleneglycol monomethyl ether,polyoxypropylene methylglucoside (for example, GlucamP10 by UnionCarbide), bisphenol A comprising ethylene oxide groups with a hydroxylvalue of about 100 to about 300, phenylglycol comprising ethylene oxidegroups with a hydroxyl value of about 100 to about 350, polyoxypropylenetrimethylolpropane with an average molecular weight of about 300 toabout 800, poly(oxyethylene/oxypropylene) trimethylolpropane with anaverage molecular weight of about 500 to about 5000 wherein each unitproportion is approximately 50 wt %, polyoxypropylenesorbitol with anaverage molecular weight of about 500 to about 3000, ethyleneoxide-added polyether-modified silicone oil, sodiumdodecylbenzenesulfonate, coconut oil fatty acid amide propylbetaine, andthe like.

The amount of the amphipathic substance may be about 0.5 to about 800parts by weight and preferably about 3 to about 600 parts by weight to100 parts by weight of water in the isotropic aqueous solution. Two ormore different amphipathic substances may also be used in admixture. Acolorless transparent isotropic aqueous solution can still be obtainedby increasing the amount of amphipathic substance added even if theamount of water is not greater than 100 parts by weight to 100 parts byweight of the amphipathic polysaccharide derivative. This is attributedto the action of the amphipathic substance as a solvent. Thus, theamount of the aqueous medium comprising water, the amphipathic substanceand a temperature shifting agent may be from about 100 to about 2000parts by weight and preferably from about 150 to about 1800 parts byweight, based on 100 parts by weight of the amphipathic polysaccharidederivative.

The initial temperature at which the molecules aggregate to produceopacity can be controlled by changing the type and amount of temperatureshifting agent, the composition of the aqueous medium (the mixingproportion of water and amphipathic substance(s)), the proportion of theamphipathic polysaccharide derivative and aqueous medium and the typeand amount of amphipathic substance(s). Examples of temperature shiftingagents include ionic substances such as lithium chloride, sodiumchloride, magnesium chloride, calcium chloride, aluminum chloride,sodium sulfate, 2-phenylphenol sodium and carboxymethylcellulose, ornonionic substances such as phenyl monoglycol, phenyl-1,4-diglycol,benzyl monoglycol, phenylpropylene glycol and 4,4′-dihydroxyphenylether, of which any two or more may also be used in admixture. Theamount thereof added is not particularly restricted, but may be up to 15wt % and preferably no greater than 10 wt % with respect to theisotropic aqueous solution. The initial opacity temperature can also bechanged by adjusting the amount of ultraviolet absorber added. Forexample, the initial opacity temperature was shifted lower by increasingthe addition of UV-106 mentioned above. Appropriate amounts ofpreservatives, antimicrobial agents, pigments, heat absorbers,antioxidants and the like may also be added as necessary.

The structure of the laminated body of the invention will now beexplained. FIG. 1, FIG. 2 and FIG. 3 are each cross-sectional views ofembodiments of a laminated body according to the invention, wherein 1 isa substrate, 2 is an isotropic aqueous solution, 3-1 and 3-2 aresealants, 4 is an air layer and 5 is an air layer seal.

FIG. 1 shows the basic mode of the laminated body of the invention,comprising an isotropic aqueous solution 2 laminated between substrates1 which are at least partially transparent and permit direct vision ofthe isotropic aqueous solution 2. The layer thickness of the isotropicaqueous solution 2 is not particularly restricted and may be about0.01-2 mm. While not shown in the drawing, there may also be positioneda spacer (for example, glass beads, glass fiber, metal wire, dottedsilicone rubber, string-like silicone rubber, etc.) between theisotropic aqueous solution 2 and the sealants 3-1, 3-2. The sealants 3consist of a water permeation-preventing layer 3-1 and an adhesivefixing layer 3-2 between the substrates. A hot-melt typepolyisobutylene-based sealant, for example, is useful for the waterpermeation-preventing layer 3-1, wherein the main resin component ispolyisobutylene and there are selected for admixture therewith resinssuch as butyl rubber, petroleum-based hydrogenated resin or polybuteneand fillers, ultraviolet absorbers and the like such as carbon finepowder, talc fine powder or silica fine powder. The properties allowextrusion working into a string-like form, and ready deformation underapproximately atmospheric pressure for bonding to the substrates. If itis too hard, string-like extrusion working may be hampered, while if itis too soft the string lines may cause flow deformation during assemblyof the laminated body, resulting in an adverse influence on the thermalstability of the laminated body. Specifically, the penetration may be15-80 mm and preferably 20-50 mm at 20° C. using a Model AP-IIPenetration Tester by Yoshida Kagaku Kiki (Specifications: JIS K2207,ASTM D5).

The adhesive fixing layer 3-2 may be a one-solution type silicone-basedsealant, a two-solution type silicone-based sealant, a two-solution typepolysulfite-based sealant, a two-solution type isobutylene-basedsealant, a two-solution urethane-based sealant, or the like. Theperformance is that of a thixotropic, highly viscous body whichadhesively solidifies onto the substrates upon hardening when allowed tostand at room temperature. The adhesive fixing layer 3-2 preferably hashigh-modulus rubber elasticity, and it may also employ a double glasssealant (for example, SE9500 by Toray/Down Corning Silicone). The waterpermeation-preventing layer 3-1 and the adhesive fixing layer 3-2 mayalso be formed in stages if necessary. This can increase the bondingstability of the water permeation-preventing layer 3-1 and is preferredfor use in harsh environments.

Any material resistant to moisture permeation may generally be used forthe substrates 1. Examples include glass panels, ceramic panels, metalplates, plastic panels, plastic films and the like, with glass includingany of the various commercially available glass materials. Combinationsof such materials may also be used for curved sections. The laminatedbody of the invention also encompasses special shapes, such as rodsobtained by injecting the isotropic aqueous solution into tubes, whichare arranged in a planar form similar to bamboo. Irregularities may alsobe formed in the substrates to vary the layer thickness of the isotropicaqueous solution 2 in order to form a raised pattern.

FIG. 2 shows the laminated body of FIG. 1 having an additional substrate1 provided and a gas layer 4 (such as an air layer) additionallysituated therein. This results in a high-performance window or wallmaterial having a heat insulating property in addition to the reversiblychanging sunlight-blocking property. When used as a window, the opaquelight-blocking property of the isotropic aqueous solution 2 in thesummer season reduces the need for indoor cooling while the lack ofopacity in the winter season allows transmission of sunlight similar toconventional glass and the gas layer 4 exhibits a heat insulating effectsimilar to conventional double glass, thereby reducing the need forindoor heating. If the additional substrate is a tile board, the opaquechange in the summer season will cause reflection of sunlight to preventtemperature increase on the wall surface, while the heat of sunlight inthe winter season will heat the tile wall surface and thus, incombination with the heat insulating property of the air layer 4, theexterior tiling will provide an effect for energy savings.

FIG. 3 shows a laminated body of the invention having isotropic aqueoussolution layers 2-1, 2-2 and 2-3 with different properties enclosedbetween the same substrates. For example, if the isotropic aqueoussolution 2 layer is separated into three sections with initial opacitytemperatures of about 30° C., about 35° C. and about 40° C. from thetop, the opacity of the window will be initiated from the top and theregion of opacity will enlarge with increasing seasonal temperature, tothus exhibit a superior sunlight-blocking effect. The layers may also besituated as lines or in a grid fashion to produce a window exhibiting apattern while simultaneously ensuring partial visibility. Even moreintricate separation can produce a continuous gradient change. Acombination of an inorganic salt (such as sodium chloride, calciumchloride or the like) and an organic substance (such asphenylmonoglycol, carboxymethyl cellulose or the like) may also be usedas the temperature shifting agent. Water-immiscible highly viscoussubstances (such as silicone oil or the like) and gel substances (suchas silicone gel or the like) may be included instead of, for example,the isotropic aqueous solution 2-1, to produce a window with constantvisibility. If necessary, string-like sealants such as used in the waterpermeation-preventing layer 3-1 of FIG. 1 may also be provided asseparators between the isotropic aqueous solutions 2-1, 2-2 and 2-3,although this is not shown in the drawing. The separators may also bereinforced by addition of reinforcing materials such as rod-shapedmetal, plastic or the like to also serve as spacers. Rod-shapedreinforcing materials containing silicone-based binders or adhesives mayalso be used. This can yield laminated bodies having the isotropicaqueous solutions clearly compartmentalized.

The laminated body of the invention may be widely utilized for buildingmaterials such as window glass, atriums, skylight windows, visors,doors, tiles and the like, as well as for articles for outdoor use,display sites such as advertisement columns, bulletin boards and thelike, and for tables, lighting fixtures, furniture, housinginstallations, miscellaneous household goods, temperature displaythermometer panels and the like. It is particularly useful for windows,including windows used in construction of houses, buildings, shops,public structures and the like, and windows for transportation vehiclessuch as automobiles, trains, ships, aircraft, elevators and the like.Needless to mention, laminated bodies according to the invention canalso serve as windows for constant blocking of ultraviolet rays whichcan cause deterioration such as discoloration of indoor articles. Whenused on wall surfaces, the wall surfaces will change depending on theatmospheric conditions at the time. For example, laminated bodies withdifferent initial opacity temperatures may be arranged in a matrixfashion to form characters, images or patterns, in order to provide newadvertisement media and guide boards which naturally undergo reversiblechange depending on the presence or absence of sunlight rays or onatmospheric changes.

The present invention will now be explained in greater detail throughthe following examples.

In the examples described below, primarily HPC is used as theamphipathic polysaccharide derivative and TP400 as the amphipathicsubstance, but the invention is not limited to these examples. In thecase of nonionic benzophenone derivatives and benzotriazole derivatives,the isotropic aqueous solutions were produced by dissolution in theamphipathic substance followed by addition of the aqueous medium andmixing, addition of the HPC and finally adequate mixing and stirring. Inthe case of ionic benzophenone derivatives and benzotriazolederivatives, preparation was by dissolution in water followed byaddition of the amphipathic substance and HPC in that order andstirring. By using multiple amphipathic substances as necessary, it waspossible to uniformly dissolve more of the benzophenone derivative andbenzotriazole derivatives in the isotropic aqueous solutions. Forfabrication of the laminated bodies, 2 mm-thick and 5 mm-thick floatglass at a size of 10 cm×10 cm were used as the substrates 1,approximately 4 g of the isotropic aqueous solution 2 was situatedbetween them in the center, and a 2.5 mm-diameter string-likeisobutylene sealant 3-1 and room temperature-reactive two-solutionsilicone sealant 3-2 were set around the periphery before pressurebonding the two substrates in a vacuum, to fabricate a laminated bodycontaining an isotropic aqueous solution free of air bubbles and havinga thickness of about 0.5 mm. The laminated bodies of the examplesdescribed below were light/weather resistant and exhibited stable anduniform reversible change. Satisfactory results were of course obtainedin an ultraviolet resistance test, in a heat resistance test at 60° C.for 5000 hours and in a cycle test with 200 cycles from −20° C. to 70°C.

The ultraviolet irradiation test for weather resistance testing wasconducted using an Eye Super UV Tester for ultra-accelerated weatherresistance testing by Iwasaki Electric Co., Ltd., at an intensity of 100mW/cm² with continuous irradiation from the 5 mm-thick substrate side ata black panel temperature of 63° C., and observation was made visually(hereinafter this will be referred to as the “UV test”). Thetransmittance was measured using a U-4000 spectrophotometer by HitachiLaboratories, which is suitable for measurement of scattered light, witha 2 mm-thick plate at the photodetection end. The transmittances weremeasured at a wavelength of 500 nm, the transparent or semi-transparentstates being measured at room temperature (hereinafter, “RT”), and theopaque states being measured after sufficient heating for saturatedopacity (hereinafter, “HT”). The amounts listed below all signify partsby weight.

EXAMPLE 1

Two separate isotropic aqueous solutions (A) and (B) transparent at 20°C. were prepared containing UV-106. Solution (A) wasHPC/TP400/UV-106/water/NaCl=50/25/1.25/87/2, and solution (B) wasHPC/TP400/UV-106/water=50/25/2.5/87. Solution (A) was colorless andtransparent with transmittances of RT: 88.7% and HT: 19.5%. The initialopacity temperature was 30° C. In the UV test, irregular aggregation wasseen immediately after continuous irradiation for 200 hours, but therewas no generation of air bubbles. The irregular aggregation disappearednaturally after standing at room temperature, and virtually no variationoccurred in the initial opacity temperature, such that a satisfactoryopaque, light-blocking state was sustained. Solution (B) was colorlessand transparent with transmittances of RT: 88.6% and HT: 13.0%. Theinitial opacity temperature was 41° C. The results of the UV test weresimilar to those of solution (A). A high degree of weather resistancewas therefore confirmed. FIG. 4 shows the transmittance (% T) at300-2100 nm for the transparent and opaque states of solution (A), for atypical transparent laminated body. This graph demonstrates thatultraviolet rays of up to about 400 nm are adequately absorbed. In orderto compare these UV test results against natural light, a laminated bodywith solution (A) was subjected to an accelerated outdoor light exposuretest with natural light (EMMAQUA Test, Arizona, USA) for 6 months, andit exhibited satisfactory results with no particular change. Theaccelerated exposure test corresponds to approximately 10 years ofoutdoor exposure in Tokyo, Japan.

EXAMPLE 2

Three separate isotropic aqueous solutions (A), (B) and (C) transparentat 20° C. were prepared containing 2,4-dihydroxybenzophenone(hereinafter, “UV-100”), 2-(2,4-dihydroxyphenyl)-2H-benzotriazole(hereinafter, “UV-7011”) and ionic functional group-containing CompoundNo. 1 mentioned above, respectively. Solution (A) wasHPC/TP400/UV-100/water/NaCl=50/50/1.25/85/1.5, solution (B) wasHPC/TP400/UV-7011/water=50/50/1.25/85, and solution (C) wasHPC/TP400/No. 1/water=50/25/1.25/87. Solution (A) was colorless andtransparent with transmittances of RT: 89.0% and HT: 12.5%. The initialopacity temperature was 31° C. The results of the UV test weresatisfactory as in Example 1. Solution (B) was colorless and transparentwith transmittances of RT: 88.6% and HT: 13.7%. The initial opacitytemperature was 42° C. The results of the UV test were satisfactory asin Example 1, although some faint yellowing occurred. Solution (C) wascolorless and transparent with transmittances of RT: 89.0% and HT:14.7%. The initial opacity temperature was 48° C. The results of the UVtest were satisfactory as in Example 1. A high degree of weatherresistance was therefore confirmed.

EXAMPLE 3

Seven separate isotropic aqueous solutions (A) to (H) were preparedcontaining the UV-106, UV-100, UV-7011 and Compound No. 1 used inExamples 1 and 2, as well as a compound obtained by adding threeethylene oxide units to the 4-position hydroxyl of UV-7011 (hereinafter,UV-7011G3). PgH represents phenyl monoglycol, PhG-55 represents phenylglycol having a polyethylene oxide group and with a hydroxyl value ofabout 165, BPE-60 represents a substance with a polyethylene oxide groupadded to bisphenol A and a hydroxyl value of about 228, and Ca-2Hrepresents calcium chloride dihydrate. Solution (A) wasHPC/TP400/PhG-55/UV-100/water/Ca-2H=50/22.5/10/2.5/86/5.5, solution (B)was HPC/PhG-55/UV-100/water/Ca-2H=50/15/2/86/10, solution (C) wasHPC/TP400/PhG-55/UV-7011/water/NaCl=50/25/5/1.5/87/2.5, solution (D) wasHPC/PhG-55/UV-7011G3/water/Ca-2H=50/50/1/86/10, solution (E) wasHPC/TP400/No. 1/water/Ca-2H=50/25/1/86/5, solution (F) wasHPC/BPE-60/PhG-55/UV-100/water/NaCl=50/20/10/1/87/3.5, solution (G) wasHPC/TP400/PhG/UV-100/water/NaCl=50/24/10/1/87/1.5, and solution (H) wasHPC/TP400/PhG-55/UV-100/UV-106/water/Ca-2H=50/22.5/10/1.25/1.25/86/5.5.Solution (A) was colorless and transparent with transmittances of RT:88.5% and HT: 12.4%. The initial opacity temperature was 29° C. Theresults of the UV test were satisfactory as in Example 1. Solution (B)was colorless and transparent with transmittances of RT: 88.5% and HT:12.5%. The initial opacity temperature was 19° C. The results of the UVtest were satisfactory as in Example 1. Solution (C) was colorless andtransparent with transmittances of RT: 88.5% and HT: 12.7%. The initialopacity temperature was 30° C. The results of the UV test weresatisfactory as in Example 1, although slight faint yellowing occurred.Solution (D) was colorless and transparent with transmittances of RT:88.3% and HT: 18.6%. The initial opacity temperature was 37° C. Theresults of the UV test were satisfactory as in Example 1. Solution (E)was colorless and transparent with transmittances of RT: 88.4% and HT:13.5%. The initial opacity temperature was 31° C. The results of the UVtest were satisfactory as in Example 1. Solution (F) was colorless andtransparent in a temperature range of 15° C. to 31° C., withtransmittances of RT: 88.6% and HT: 15.6%. It was opaque even at below15° C. The results of the UV test were satisfactory as in Example 1.Solution (G), due to the action of PhG, exhibited visibility between 18°C. and 29° C. with a light whitish blue semi-transparent state andtransmittances of RT: ˜70% and HT: 11.7%. The temperature of the initialstrong opacity was 29° C. It was also opaque at below 18° C. The resultsof the UV test were satisfactory as in Example 1. Solution (H) wascolorless and transparent with transmittances of RT: 88.5% and HT:12.1%. The initial opacity temperature was 29° C. The results of the UVtest were satisfactory as in Example 1. Incidentally, the opacity changein low temperature ranges with solutions (F) and (G) was observed evenwhen UV-100 was removed, and the change was stably reversible.

COMPARATIVE EXAMPLE

There were prepared two separate isotropic aqueous solutions (A) and (B)containing no ultraviolet absorber and two separate isotropic aqueoussolutions (C) and (D) containing Sumisorb 111S (hereinafter, “110S”) bySumitomo Chemical Co., Ltd. Solution (A) wasHPC/TP400/water/NaCl=50/25/87/2, solution (B) wasHPC/TP400/water=50/25/87, solution (C) wasHPC/TP400/110S/water=50/25/2.5/87, and solution (D) wasHPC/TP400/110S/water=50/25/1.25/87. Solution (A) contained noultraviolet absorber and had transmittances of RT: 88.5% and HT: 13.7%.The initial opacity temperature was 34° C. In the UV test, air bubbleswere generated after 50 hours producing an irreversible change, whilegeneration of larger air bubbles occurred after 100 hours therebyhampering opaque change, and the state was irreversible. Solution (B)contained no ultraviolet absorber and had transmittances of RT: 88.5%and HT: 13.7%. The initial opacity temperature was 46° C. The results ofthe UV test were the same as for solution (A). Solution (C) wascolorless and transparent with transmittances of RT: 88.0% and HT:17.2%. The initial opacity temperature was 52° C. In the UV test, theinitial opacity temperature increased to 62° C. after 50 hours, whilegeneration of air bubbles occurred after 100 hours thereby hamperingopaque change, and the state was irreversible. Solution (D) wascolorless and transparent with transmittances of RT: 89.1% and HT:18.9%. The initial opacity temperature was 49° C. The results of the UVtest were the same as for solution (C). Thus, even addition of 110Sproduced only a slight degree of improvement, leaving an obvious problemfor extended use. In order to compare these UV test results againstnatural light, laminated bodies with solutions (A) and (C) weresubjected to the aforementioned EMMAQUA Test for 6 months, and similarto the UV test, an irreversible state was exhibited by both.

INDUSTRIAL APPLICABILITY

According to the present invention, laminated bodies enclosing isotropicaqueous solutions containing selected benzophenone derivatives andbenzotriazole derivatives exhibit high weather resistance while stablymaintaining uniform reversible changes, and they are therefore practicalfor such purposes as windows, visors, tiles and the like which are usedfor long periods under constant exposure to direct light rays from thesun.

1. A laminated body comprising an isotropic aqueous solution obtained bydissolving 100 parts by weight of a water-soluble polysaccharidederivative having a weight-average molecular weight of about 10,000 toabout 200,000 and having a nonionic amphipathic functional group, inabout 100 to about 2000 parts by weight of an aqueous medium composed ofwater in an amount of about 25 to about 450 with respect to 100 parts byweight of said polysaccharide derivative and an amphipathic substancewith a molecular weight of about 60 to about 5000, laminated betweenplates that are partially transparent and allow direct vision of saidaqueous solution, wherein there is added in an amount of 0.01-10 partsby weight with respect to 100 parts by weight of said isotropic aqueoussolution at least one compound selected from the group consisting ofnonionic benzophenone derivatives and benzotriazole derivatives havingsolubility of 1 g or greater in the amphipathic substance at 20° C. andionic benzophenone derivatives and benzotriazole derivatives with anionic functional group bonded to the benzene ring via a chain portionand having solubility of 1 g or greater in water at 2° C.
 2. A laminatedbody according to claim 1, wherein said nonionic benzophenone derivativeor benzotriazole derivative has 2° C. solubility of 1 g or greater inthe amphipathic substance polyoxypropylene trimethylolpropane having amolecular weight of about
 400. 3. A laminated body according to claim 1,wherein said nonionic benzophenone derivative or benzotriazolederivative is a compound represented by the following general formula 1or
 3.

(wherein R₁ and R₂ each represent hydrogen or hydroxyl, with at leastone of R₁ and R₂ being hydroxyl, and R3⁻Rio each represent hydrogen,C₁₋₄ alkyl, C₁₋₄ alkoxy, hydroxyl, polyglycerin, polyethylene oxide orO—(R₁₁)_(n)-A (where A represents an unprotected sugar residue (aresidue lacking one hydroxyl group from, for example, a monosaccharidesuch as glucose or galactose, a disaccharide such as trehalose ormaltose or a trisaccharide such as maltotriose), and R₁₁ represents adirect bond (n=0), C₁ _(—) ₄ alkylene or C₁ _(—) ₄ alkyleneoxide (wheren is an integer of 1 to 6)), with at least one from among R₃ to R_(io)being hydroxyl, polyglycerin, polyethylene oxide or 0-(R11)n-A);

(wherein R₁ represents hydroxyl, and R₃—R₆ each represent hydrogen, C₁₋₄alkyl, C₁₋₄ alkoxy, hydroxyl, polyglycerin, polyethylene oxide or0-(R11),,-A (where A represents an unprotected sugar residue (a residuelacking one hydroxyl group from, for example, a monosaccharide such asglucose or galactose, a disaccharide such as trehalose or maltose or atrisaccharide such as maltotriose), and R11 represents a direct bond(n=0), C₁₋₄ alkylene or C₁₋₄ alkyleneoxide (where n is an integer of 1to 6)), with at least one from among R₃ to R₆ being hydroxyl,polyglycerin, polyethylene oxide or O—(R11)n-A).
 4. A laminated bodyaccording to claim 1, wherein one from among R₃ to R₆ and one from amongR, to R_(io) are hydroxyl groups.
 5. A laminated body according to claim4, wherein the remaining groups of R₃ to R₆ and R, to R_(io) arehydrogen atoms, methoxy groups or ethoxy groups.
 6. A laminated bodyaccording to claim 1, wherein the ionic functional group is a sulfonicacid group, carboxylic acid group, phosphoric acid group or ammoniumgroup.
 7. A laminated body according to claim 1, wherein a temperatureshifting agent is further added to said isotropic aqueous solution.
 8. Alaminated body according to claim 1, wherein two or more differentisotropic aqueous solution layers are provided.
 9. A laminated bodyaccording to claim 1, wherein an additional substrate is situated on atleast one side to provide a gas layer.
 10. A window containing alaminated body which comprises an isotropic aqueous solution obtained bydissolving 100 parts by weight of a water-soluble polysaccharidederivative having a weight-average molecular weight of about 10,000 toabout 200,000 and having a nonionic amphipathic functional group, inabout 100 to about 2000 parts by weight of an aqueous medium composed ofwater in an amount of about 25 to about 450 with respect to 100 parts byweight of said polysaccharide derivative and an amphipathic substancewith a molecular weight of about 60 to about 5000, laminated betweenplates that are partially transparent and allow direct vision of saidaqueous solution, wherein there is added in an amount of 0.01-10 partsby weight with respect to 100 parts by weight of said isotropic aqueoussolution at least one compound selected from the group consisting ofnonionic benzophenone derivatives and benzotriazole derivatives havingsolubility of 1 g or greater in the amphipathic substance at 20° C. andionic benzophenone derivatives and benzotriazole derivatives with anionic functional group bonded to the benzene ring via a chain portionand having solubility of 1 g or greater in water at 20° C.
 11. A windowaccording to claim 10, wherein said nonionic benzophenone derivative orbenzotriazole derivative has 2° C. solubility of 1 g or greater in theamphipathic substance polyoxypropylene trimethylolpropane having amolecular weight of about
 400. 12. A window according to claim 10,wherein said nonionic benzophenone derivative or benzotriazolederivative is a compound represented by the following general formula 1or
 3.

(wherein R₁ and R₂ each represent hydrogen or hydroxyl, with at leastone of R₁ and R₂ being hydroxyl, and R₃-R₁₀ each represent hydrogen, C₁_(—) , alkyl, C₁ _(—) , alkoxy, hydroxyl, polyglycerin, polyethyleneoxide or O—(R₁) n-A (where A represents an unprotected sugar residue (aresidue lacking one hydroxyl group from, for example, a monosaccharidesuch as glucose or galactose, a disaccharide such as trehalose ormaltose or a trisaccharide such as maltotriose), and R II represents adirect bond (n=0), C₁ _(—) , alkylene or C₁ _(—) , alkyleneoxide (wheren is an integer of 1 to 6)), with at least one from among R₃ to R_(io)being hydroxyl, polyglycerin, polyethylene oxide or O—(R11)n-A);(wherein R₁ represents hydroxyl, and R₃-R₆ each represent hydrogen, C₁_(—) , alkyl, C₁ _(—) , alkoxy, hydroxyl, polyglycerin, polyethyleneoxide or _(O-(R11)n-A) (where A represents an unprotected sugar residue(a residue lacking one hydroxyl group from, for example, amonosaccharide such as glucose

or galactose, a disaccharide such as trehalose or maltose or atrisaccharide such as maltotriose), and R11 represents a direct bond(n=0), C₁ _(—) , alkylene or C₁ _(—) , alkyleneoxide (where n is aninteger of 1 to 6)), with at least one from among R₃ to R₆ beinghydroxyl, polyglycerin, polyethylene oxide or 0-(R11),-A).
 13. A windowaccording to claim 10, wherein one from among R₃ to R₆ and one fromamong R, to R₁₀ are hydroxyl groups.
 14. A window according to claim 13,wherein the remaining groups of R₃ to R₆ and R, to R₁₀ are hydrogenatoms, methoxy groups or ethoxy groups.
 15. A window according to claim10, wherein the ionic functional group is a sulfonic acid group,carboxylic acid group, phosphoric acid group or ammonium group.
 16. Awindow according to claim 10, wherein a temperature shifting agent isfurther added to said isotropic aqueous solution.
 17. A window accordingto claim 10, wherein two or more different isotropic aqueous solutionlayers are provided.
 18. A window according to claim 10, wherein anadditional substrate is situated on at least one side to provide a gaslayer.